Large amounts of energy is being expended and wasted every single day. While the world’s greatest engineers work tirelessly to find new sources of renewable energy, Team Limitless is working to harness some of the unused energy in everyone’s daily life. The Swopper charger project looks to take the currently unused energy that is expended when people sit down and convert it into usable power to charge personal electronic devices.
Basic requirements that are key in the design phase of the project include maintaining the chair’s current functionality, compliance with all relevant safety standards and codes, and the system has to produce electricity from some form of energy used when sitting in a chair. These and many more design specifications are an integral part of the project.
Proof of Concept
The Via Seating Swopper Charger belongs to the furniture manufacturing industry, specifically ergonomic seating. Many people sit for long hours in a work environment and ergonomic seating can prevent workplace injuries such as carpal tunnel, muscle strains and low back injuries. Companies tend to purchase ergonomic seating for their employees to prevent injuries and provide a safer work environment. There are several companies who factor ergonomics in their seating, but not many of them have the capability to capture wasted energy from the motion. Team Limitless has completed the product design specification, hazard identification, functional decomposition, and morphological chart to determine the best design to enter the market. The team has decided on two types of designs that focuses on their respective main component: an electrical machine and a piezoelectric material to generate electricity.
Team 4 is using a mathematical model to determine the practicality, efficiency, and utility of a piezoelectric pressure plate on the Swopper chair from Via Seating. The piezoelectric plate creates a voltage in response to a mechanical force, which would allow the charger to capture the compressive forces from a person sitting on the chair and convert it into usable electrical energy. With these principles in mind, Team 4 is running mathematical tests to determine the number of compressions needed to charge a cell phone battery and, based on the number of times people sit down on chairs in a typical 8 hour work day, determine the amount of time needed to charge a cell phone battery.
Once the design is refined and proven to work, this technology can be utilized in any setting that uses office chairs such as offices, laboratories, reception areas, etc. One market that has potential regarding this technology would be college campuses and other educational facilities. In these settings, students sit down in chairs repeatedly throughout the day, which could potentially build up enough energy to supply power to small parts of the buildings, reducing the electricity bill.
Figure 1: SolidWorks drawing of the pressure plate. All dimensions are in mm.
Fig. 1 shows the SolidWorks model of the pressure plate to be mounted on Via Seating’s Swopper chair. This will be mounted at the base of the center spring, so that the plate can capture the maximum amount of compression force, thus producing the maximum electrical voltage. Wires will follow the inside of the spring up to the underside of the seat cushion, where the plate will connect to a voltage regulator, which will connect to the rechargeable battery.
Team Limitless is designing a system that will convert mechanical energy into usable electrical energy. This revised design and prototype are based on the Swopper Chair from Via Seating and will utilize the energy from sitting in and compressing the Swopper Chair to turn a generator shaft. The generator will produce electricity from this mechanical motion, which will then be collected and stored in a portable cell phone charger.
The Swopper Charger allows the end user to charge a personal electronic device, such as a cell phone, without being plugged into a wall for power. This is convenient for the end user because this mobile capability eliminates the need to either be near a wall to charge a phone or be away from the phone while it charges. The charger system for the Swopper chair allows the chair to be moved to any location in an office, home, shop, etc. without losing the ability to charge a phone or other personal electronic device.
The Swopper Chair Charger is required to meet certain design specifications in order to be considered a successful product. These specifications include maintaining basic chair functionality, electricity generation, safety enclosure, among other requirements as defined by Via Seating and Team Limitless.
Fig. 1 – Exploded view of Charger design
Figure 1 shows an exploded view of the system components excluding the safety enclosure to be included on the Swopper chair. The design includes capturing energy from the compression from sitting on the chair and using it to spin a pulley. This pulley is connected to a smaller pulley using a belt and spins the smaller pulley, which is attached to the generator shaft. The generator will then be wired to the portable phone charger, which will be the point of connection for the end user to plug in the cell phone or other electronic device. Figure 2 shows the system as a complete assembly (minus the enclosure and phone charger).
Fig. 2 – Assembled view of Charger system
The fabrication process for the Swopper Charger will consist of assembling the pulley setup that will be utilized in the prototype. First, the small pulley will be mounted to the shaft of the generator to act as the mechanism that spins the generator to produce power. Next, the large pulley must have the ball bearing press fit into it to allow the pulley to spin freely while mounted to the chair. From here, the pulleys will be placed 6 inches apart, center to center and the belt will be fitted to the pulleys. There will be a mount to support the large pulley from the spring of the chair and a mount to support the generator from the spring of the chair. Some wiring will be required to connect the battery to the generator, which will allow for the system to store the electricity generated. The final component of this assembly will be a system to connect the corkscrew rod to the base of the seat, ensuring that energy from every compression of the seat will be captured and utilized.
Figure 1 shows most of the components pre-assembly, showing the pulleys, generator, belt, corkscrew, turnkey, battery and charging cable. Figure 2 gives a more detailed look at the large pulley and the notches created so that the corkscrew can effectively turn the pulley.
Fig. 1 – Pre-assembly components
Fig. 2 – Large pulley
Testing and Results
Meet the Team
Originally from Fallon, NV, Nicole moved to Reno to pursue a degree in mechanical engineering at UNR. Her academic career at UNR has been both challenging and exciting. Nicole has developed her skills using CAD software and has become a Certified SolidWorks Associate. She has also made the dean’s list twice and has interned with Baker Hughes, a GE Company in Minden, NV. Nicole’s most challenging engineering project has been the Swopper Charger, but she fully enjoys the challenge and is excited to work with her team to produce a prototype for Innovation Day. After graduation, Nicole hopes to find an engineering position in manufacturing or working with renewable energy.
Andrew was born and raised in Rocklin, California but moved to Reno in 2013 to attend the University of Nevada, Reno. Throughout his academic career, Andrew has developed and refined his critical thinking and problem solving skills. Andrew is proud to say that he is able to provide for his wife and 2 year old daughter while finishing up his final year of college. The most challenging project that Andrew has worked on is a project from his current job at Applied Mechanical, Inc. The project was a remodel of a pizza kitchen’s ventilation system and required a lot of coordination and communication. Andrew’s current goals include passing all of his classes for Fall 2018, passing the FE exam in January, and making Dean’s List for Spring 2019. Future goals include passing the PE exam in HVAC and running a mechanical contracting firm.
Nelson “Jay” Aquino
Jay was born in the Philippines and raised in Reno, Nevada. He spontaneously decided to pursue an engineering degree and found himself to be interested in both mechanical and electrical systems, which he now majors and minors in respectively. Jay’s current goal is to obtain experience during Winter and Spring in preparation for graduation, pass the FE exam, and obtain a position to work in mechanical/electromechanical systems after graduation. His most challenging engineering project has been the Capstone Swopper Charger, but he is learning practical communication, writing, and technical skills to apply in the real world.
Jorden was born and raised in Reno, Nv. He has always enjoyed math and problem solving, which lead him to pursuing a degree in engineering. Jorden is very proud of the many multi pitch rock climbs he has conquered. Jorden’s current goal is to do well on his GRE so he can pursue a Masters degree in Aerospace Engineering. His future goals are to gain experience through working as an engineer in the aerospace field and to develop a faster and safer way to fly. His most challenging engineering project has been developing a functioning and accurate MATLAB code to calculate flow over an airfoil; however, he enjoys the challenge and is working diligently to have an outstanding knowledge of the topic. Over his academic career Jorden has improved his critical thinking skills and problem solving skills. He has learned many new skills in MATLAB and ANSYS during his academic career.
Shara was born in Reno, Nevada and spent 9 years in the military as an Avionics Technician. After her discharge from the military, Shara decided to return to school to pursue a degree in Mechanical Engineering from the University of Nevada, Reno. Shara’s most challenging engineering project to date has been the Swopper Charger project for the UNR Capstone course, and the problem solving skills taught at the University have prepared her for this significant project. The UNR Engineering curriculum has refined Shara’s communication skills and improved her ability to convey critical information and ideas to coworkers and peers. Upon graduation from the University, Shara plans to pursue a career in the Mechanical Engineering field.